This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project investigates sex differences in the social, emotional, cognitive and neuroendocrine consequences of neonatal and post-pubertal amygdalectomy in rhesus monkeys living in complex semi-natural social groups. Unlike the severely socially restricted conditions of previous studies, our large monkey groups have multiple matrilines and all age and sex classes allowing investigating amygdala function under social conditions it is likely designed to deal with. This project tracks the development of these systems and relates changes in juvenile function to the pubertal transition and adult social behavior. Forty-eight monkeys, distributed between 8 male and 8 female controls, 8 neonatally amygdalectomized of each sex, and 8 post-pubertally lesioned subjects of each sex, will be created in two annual cohorts of 24. Neonatal gonadal function, anxiety, fear, and maternal attachment will be assessed along with extensive observations of social interactions in the subjects'natal group during the first four years of life. At 2yr, cognitive continuously available computer kiosks will be used to assess object and spatial memory span and object discrimination. At 2yr females will be intensely sampled to assess pubertal timing as well as pubertal changes in social and sexual behavior. It is hypothesized that the different male and female natal social environments, combined with the sexually differentiated nature of amygdala function will produce different magnitudes of effect of amygdala damage, with males being more severely affected than females. During the first year of funding 6 surgical control and five (4 male, 1 female) amygdalectomized subjects were created. Weekly focal observations of behavior, neonatal imitation, and LabTab performance has been collected on these subjects. Sample sizes will not be sufficient for data analysis until the completion of this birth season when the additional subjects will be created.